Commutator-rocking device



- June. 17, 1930. c, WHWTAKER 1,764,376

COMMUTATOR ROCKING DEVICE Filed June 29, 1928 2 Sheets-Sheet l IIIIIII IH Hill lllllll IN V E N TO R Char/66C. h/b/flalrf ATTORNEY Patented June 17, 1930 UNITED STATES VANIA PATENT OFFEQE PENNSYLVANIA, ASSIGNOR T0 WESTING- COB-PORATION OF PENNSYL- COMMUTATOR-ROCKING DEVICE Application filed June 29,

My invention relates generally to control systems and particularly to the control of the driving motors of electric locomotives.

In the operation of heavy trains on electri lied railways, it is common practice to enrploy one locomotive at the head of the train and another pushefl locomotive at the rear of the train. It often happens that power is applied to the motors of one locomotive be fore it is applied to the motors of the other locomotive and, since a single locomotive is incapable oi moving the train, the motors to which power is applied cannot rotate and the current supplied through the brushes flows continuously through the same commutator bars. When the entire motor current continuously flows through a single commutator bar for a period of time, excessive heating occurs and, as a result, the commutator bar may warp.

The object of my invention, generally stated, is to prevent heating the commutator bars or motors during the starting period, ii: the load cannot be immediately set in motion.

A more specific object of my invention is to provide for rocking the commutator cylinders of traction motors after power is applied and before the train is moved.

A further object of my invention is to proride for varying the torque exerted by the individual motors of a group without varying the total torque of the group of motors.

Another object of my invention is to provide for increasing the voltage across one motor as the voltage in another motor decreases a corresponding amount.

It is also an object of my invention to pro-- vide a motor-querated variable resistor for controlling the voltage applied to a driving motor which shall be rendered inactive upon n'ioven'ient ot' the driven load.

Other objects of my invention will become apparent to those skilled in the art when tl following description is considered in col junction with the accompanying drawing, in which:

Figure 1 is a view, in side ele\*ation, of a traction motor geared to a driving wheel and an auxiliary contact device;

1928. Serial No. 289,317.

an end view of the auxiliary contact device shown in Fig. 1;

Fig. 3 is a diagrammatic view of a control sstem, for controlling a group of traction motors, connected in accordance with my invention;

Fig. 1 a sequence chart showing the sequence of closure of the switches embodied in the system shown in Fig. 3;

i". 5 is a view, in side elevation, of the for a locomotive; and

is a view, in end elevation, of a portion of? a locomotive driving wheel showing the c riving gear connected to the driving wheel tirough a series of springs.

Referring now to the drawings, a traction motor 10 mounted upon an axle 11 of a locomotive lriving wheel 12. The motor 10 is connecte to drive the locomotive driving wheel through a pinion 13 and a gear 14 resiiientiy connected to the locomotive driving wheel 12 in any suitable manner well known in the art, such. as that shown in Figure 5.

The traction motor 10 is connected, through gear 15 and a centrifugally-oper ated clutch. member 16, to an auxiliary contact device 17. The contact device 17 is pro vided with an outer drum 18 and an inner drum 19, shown clearly in Fig. 2.

Che cen"ritugally-operated clutch mechanism 18 transmits motion to the inner drum 19 which is connected, through a series of springs 20, to the outer drum 18. The outer drum 18 and the inner drum 19 of the auxiliary contact device are mounted concentrically upon a shaft 21, and a brace member 22 is rigidly connected to the outer drum 18 and tree to move on the shaft 21.

A. star-wheel 23 is rigidly attached to the brace member 22 and coacts with a pawl 24 to restrict the motion 01'' the outer contact drum 18 and stop it ata desired point.

iiig. 2 is When an oscillating motion occurs in the motor 10, it is transmitted, through the gear 15 and the clutch 16, to the inner drum 19 of the auxiliary contact device 1'? which may be moved relative to the outer drum 18 because of the flexibility of the springs 20 whichcon- In this way,

nect the two drums together.

the outer drum 18 is prevented from moving during such oscillation unless the amplitude of the oscillation is suflicient to cause the tension in the springs 20 to overcome the force of the pawl upon the star wheel 23 and cause the outer drum 18 to advance a notch.

It will be apparent that, when the motor begins its unidirectional operation, sui' ficient tension will be exerted continuously upon the springs to cause the outer drum 18 to more with the inner drum This rendition, however, will exist only until th* centritanally-operated clutch member 16 becomes connected from the inner drum 19 when the motor 10 reaches a predetermined speed.

The outer drum 18 ot the auxiliary contact tlC' re 1? is provided with a plurality of contact plates 25 mounted on its outer surface and insulated therefrom. A pair of congers are disposed to engage the contact tact plates 25 when the outer drum 18 is moved to a predetermined position. The star-wheel 23 and the pawl Bl coact to stop the outer drum 18 in position where the contact lingers 26 will stand between two of the contact plates Since the contact fingers r36 engage the contact plates 25 only when the drum 18 is being lvanced and the pawl over a tooth of the star wheel, and such engagement exists for a relatively short period of time because oi. the action of the wings 20 between the outer drum 18 and the inner drum l9.

traction motor 10 represents one of a group of traction motors 10, 27, 28 and 29, shown connected in the circuits 01 Fig. 3 and disposer. to be operated together, as will be nest; ibed hereinafter.

Tl llC-H the traction motor 10 is operated,

p0 ver is transmitted, through the pinion 13, the driving gear wheel 1% and the spring 30, to the driving wheel 12. This method of connection provides a resilient drive and enables the motor to have a slight movement to com press the spring before the driving wheel ii is set into motion. The relative movement between the driving gear wheel 1-1 and the dri wheel 12, which is permitted through the ilenibility the sprin enable the motor 10 to advance through an gle e1} uivalent to four or five of the cominutator bars 31.

T he commutator bars 81 are engaged by a pair or brushes 32 through which current is ed to the armature of the motor 10. power is initially applied to the brushes the traction motor 10, the rotor rotates e; or and advances the driving gear wheel 1st to compress the spring 30 and, it the train behind :he locomotive is so heavy that the drivingwheel 12 will not rotate, the motor 10 comes to a standstill, with power still being through its brushes 32, so that ourapplied rent continuously through the same g 30, is sutlicient to' connnutator bars as long as the motor stands in this position.

v invention provides a method of varying the power applied to the motor 10 dura starting period when the torque exerted by the group of motors l0, 2?, 2S and 29 is insullicient to set their iorreeponding driving in. '3. he variation in power "e motors 1O, 27, 2S and 29, .m will be described only in in witn the motor 10. on the initial application of voltage to the motor 10, the driving ear wheel 14 is adto comprcs pring 30 and establish a state of equilibrium between the torque exerted by the motor 10 and the spring 30. It now, the voltage applied to the motor 10 be increased or deer sad, the spring 30 will e respectively co ,resscd or released to an correspondi to the variation in the torque exerted by the motor, consequent to chances of voltage. in this way, the commu tato iinder may be rocked when a variation in the volt e across the bi shes occurs and causes an crease or decrease in the torque the motor 10.

ors and 31 are relation with the 29, respectively, ge applied. The variable re-- 2:323 and Z i are operated by a motor in such manner that, as the resistance in one meter circuit is increased, the resistance in the other is decreased a co spending amount. In t way, the voltage across the motors 10 and may be increased when the voltage across the motors and is decreased.

f urthermore, the sum of the voltage acro s the motors l0 and 2? and the voltage acr t the motors 28 and will be maintained at a constant value and, in this way, the total torque exerted by the group of motors will remain at a alue during the period in which the vol 'e applied to the respective motor armature being var ed to produce a rocking of their respective commutator cylinders.

The motor dr ht-hand and let M ii, moves it alternately right and left, as viewed in the drawing.

The cross arm provided with insulators 4:0 on which are mountedcontactmembcrs l1 and L2 to eng ge the resistors 33 and 3t. respect ely. its the cross a in 39 is moved from right to left, the amount of the res stor 33 which is connected in circuit is increased while the amount of the re ..,tor 34:, which is connected in circuit, is decreased a corre- 37, as the scr w meini-r 36 rotates continuously in the same d es-' r and thereby sponding amount, while the opposite variation occurs when the cross arm 39 is moved from left to right.

The supply circuit for the motors 10, 27, 38, 29, and 35 is shown in Fig. 3and, inasmuch as the particular auxiliary control system which may be utilized to eitect the desired main circuit connections is not a part of my present invention and may be readily supplied by those skilled in the art, I do not deem it necessary to illustrate or describe the same. The following description of the circuit connections, when taken in conjunction with the sequence chart shown in Figure i, will give a clear explanation of the circuits established during the functioning of the invention.

The primary winding of the transformer 43 is connected between the trolley and ground conducto s from which it receives its supply of power. The secondary winding of the transformer 43 is provided with a plurality of taps from which a variable voltage may be obtained by closure of any of the desired switches 44- to 0-9. The switches 44 to 59 may be closed, in accordance with the sequence chart, to apply an increasing voltage to the traction motors 10, 27, Q8 and 29 during the starting period.

The operation of the transformer switches =14. to is accomplished through the operation of a master controller or sequence switch, in a manner well-known in the art, to control the operation of the traction mo tors 10, Q7, 28 and 29.

Upon the actuation of a master controller to its first position, the switches indicated in step a of the sequence chart are actuated, that is, the auxiliary switch MC, the motor switches 60 and 61 and the interlocking contact members ("30a and (ila are closed. When the master controller is advanced to its sec ond position, the switches noted in step b, in thesequence chart, are operated to close the transformer switches 44:, 45, 46 and i7 and interlock contact member 47a, and a starting voltage of low value is supplied to the traction motors 10, 27, 28 and 29, through the preventive coils 62 and conductor 63 to impart an impulse to the armatures of the traction motors. A

Upon the closure of the interlocking contact member 61a, a circuit is completedwhich may be traced from the tap (ii of the transformer 43, through conductor 65, motor 35, conductor 66, interlocking contact member 700, the contact member of the time element relay 6'7, interlocking contact member 61a and by conductor (38, to the tap 69 of the transformer 43, thereby supplying power to the auxiliary motor and operating the variable resistors 33 and 34 to vary the voltage applied to produce an oscillation of the commutators of the traction motors 10, 27, 28 and 99, in case the power suppliedis insuflicient to set the driving wheels 12 into" motion, as described above.

iVhen the driving wheels 12 are finally set into motion, the contact device 17 is rotated until the centrifugal clutch 16 is disengaget The centrifugal clutch 16 may be adjusted to become disengaged at any predetermined speed of the traction motor 10. In this par 'ticular embodiment, the clutch 16 will be considered disengaging the inner drum 19 at a speed which cannot be attained until the switch is closed, or that is at the control position :i of th 1 sequence chart if the motors are operating at their full speed corresponding to this voltage. When the outer drum 18 of the contact device 17 advances,

one contact fingers 26 are momentarily brit ged by the contact plate 25, and a circuit ZS illishod which may be traced from the battery Ti, through the switch MC, the conta fingers 26, bridged by the conductor plate 25s, the operating coil of the time-elet relay 6'7, interlocking contact 17a and locking contact (30a, returning to the opminal of the battery 71. This cirwts for only the period of time which --d ior the outer drum 18 of the conice l"? to advance across the contact l Y 7 but suiicient to energize the operatmg coil of the time-element relay 67 and actuate its contact members into their circuit--interrupting position, thereby interrupi'in t e supply of energy to the motor ne i e-element relay 67 is provided with oa zhpct "Z2 having a valve 73 which permits an unrestricted upward motion of the relay but rds its downward travel when the opcoil is deenergized.

V hen the motor 10 has started its load, the outer drum 18 of the contact device 17 will be advanced rapidly enough to complete the circuitfor the energizing coil of the time element relay so often that the frequency of the impulsi in conjunction with the action of the dash-pot 72, maintains the contact members in their open position.

Since the centrifugal clutch 16 is adjusted to be disengaged from the inner drum 19 of contact device 17 approximately the time mat the switch 55 is closed, it will be observed from the sequence chart that the interlocking contact member 7060 is actuated to its circuit-interrupting position at substantially the same time that the control position j is reached and the switches 7 O and T4: are actuated to their closed positions to bypass the variabie resistors 33 and ill, re-

specs. ely, during the same control position. n till}; way the operation of the motor 35 traction motors may be accelerated until full voltage is applied across their terminals, as shown in the control position 1% of the sequence chart.

The interlocking contact member 51a is operated simultaneously with the switch 51, as shown in the sequence chart, and is disposed, when in its closed position, to by-pass the interlocking contact member To. The interlocking co tact member 5164 is actuated to its open position simultaneously with the interlocking" contact member 70a, as shown in position j of the sequence chart. In this way, the supply cir s -for the relay 67 and the motor are interrupted at approximately the same time the clutch 16 is dis engaged.

It will be readily ur ierstood that such dcvice for varying the torque in a traction motor and thereby rocking its armature against the flexibility of a resilient drive may be applied to any number of motors and is not limited to the speci arrangement shown herein. Neither is too so tern limited i application to motor iron from an alternating source of pow shown in this embodiment, but may be r ar 7 applied to lirect-current systems.

The embodiment may be further modified and a iplied to other types of drives tl :l one described hereinbet'ore, without.departing from the spirit and scope of the invention, and it desired that the foregoing description shall be construed as illustrative and not in a limiting sense.

claim as my invention:

1. In a motor-control system, in combination, a plurality of driving motors provided with armatures and commutators, a source of power for the motors, means for connecting the motors to the source or power, means for va the volts applied to the motors appli d to one motor voltage applied to another "IOI'Q V vary the torque in the sto motor 8.310 a ,tsilient drive connecting the motors to the load, said resi-.ent drive and variable torque coacting to oscillate the motor armature and connnutatoi' during the starti ot' the motor.

in a motor-control system, in combinalion, a plurality driving motors provided with arma and commutators, a source of power tor l the motors. a resilient drive for connecting t 1 I m for continue aoplied the motors, eoope resilient drive to .e rue motors an oscillatory mo tion.

3. In a motor-centre pom, in combination, a plurality of dri ving motors provided with armatnrcs and conn ators, a source of power for the motors, a resilient drive connecting the motors to the load, means for varying the torque exerted by motors upon the resilient drive, whereby the armature and the commutators of the motors may be rocked against the resilient drive, said torque-varying means being disposed to maintain a constant total pull or" the motors on the load during the period oi rocking.

4. In a motor-control system, in combination, a. plurality of driving motors provided with armatures and commutators, a source of power for the motors, a plurality of resilient drives connecting the motors to the load, means for varying the torque exerted by the respective motors upon the resilient drive, whereby the armatures and the commutators ot the motors may be rocked against the flexibility of the resilient drives, said torque varying means being disposed to maintain a constant total pull of the motors on the load during the period of rocking, and means for rendering said torque-varying means inoperative when the load is actuated.

In motor-control system, in combinaof power for the n'iotors, a variable resistor cted in circuit with each of said motors, us for operating! said resistors to alterincreae a nd decrease the resistance of z r to -;:orrespondingly decrease one or as another increased, thereby varyne torque in each motor without varying ii torque.

a motor-control system, in combinati in. a plurality 01 (11" mg motors provided armatures and eommutators, a source of '-r the motors, a resilient drive conting the motors to the load, a variable re- .tor connected in circuit with each of the motors, means for o -iierating said resistors to alternately increase and decrease the resis tance of each, and to correspondingly de crease one resistor as another is increased, tiereby varying the torque exerted by each motor without varying the total torque, said 1 t 'esilient drive and variable torque coacting o continuously oscillate the motor armatures and commutators, during the starting of the motors.

'7. In a motor-control system, in combination, a plurality of driving motors provided with armatures and ccmmutators, a source of power for the motors, a resilient drive connecting the motors to the load, a variable reor connected in circu t with each of the rotors, means for operating said resistto alternately increase and decrease the resistance in the motor circuits, and to correspondingly decrease the one motor circuit as the res ance in another is increased, thereby varying the torque exerted by the individual motors without varying the total torque, said resilient drive and variable torque coacting to oscillate the armatures and commutators during motor the respective the starting period and means for rendering said torque-varying means inactive when the load is in motion.

8. In a motor-control system, in combination, a driving motor provided with a commuta! or cylinder and brushes disposed to engage the commutator cylinder, a resilient drive through which the motor exerts its driving action and means for varying the torque of the motor thereby to unbalance the driving forces delivered by the motor and the reactive forces of the resilient drive to cfl oct an oscillatory movement of the commutator cylinder relative to the brushes to distribute the heating of the commutator.

9. In a motor-control system, in combination, a driving motor provided with a commutator cylinder and brushes disposed to ride on the commutator cylinder, a resilient drive through which the motor acts, and means for unbalancing the forces exerted by the motor and resilient drive to effect arc oscillation of the commutator cylinder relative to the brushes to distribute the heating of the commutator cylinder during the starting of the motor.

10. In a motor-control system, in combination, a propelling motor provided with a commutator cylinder and brushes disposed to engage the commutator cylinder, means for varying the torque delivered by the motor during starting and a drive for receiving the torque of the motor, said drive bein adapted to deliver a varying reactive force to the motor when receiving a vary torque, whereby the commutator cylinder is oscillated relative to the brushes to distribute heating during the starting of the motor.

11. In a motor-control system, in combination, a plurality of driving motors, said motors being provided with commutator cylinders and brushes disposed to engage the commutator cylinders, a plurality of resilient drives for connecting the motors to a common load and means for unbalancing the forces e):- erted by the respective motors and resilient drives without varying the total effort exerted by the motors to move the load, whereby the commutator cylinders of the respective motors are oscillated relative to the brushes to distribute the heating of the commutators during the starting of the motors and before the load is moved.

12. In a motor-control system, in combination, a plurality of driving motors, said motors being provided with commutator cylinders and brushes disposed to engage the commutator cylinders, means for varying the torque delivered by the respective motors during starting without varying the total torque of the motors during starting, and a drive for connecting the respective motors to a common load, said drive being adapted to deliver a varying reactive torque, whereby a constant efiort to move the load is maintained and the commutator cylinders are oscillated relative to the brushes to distribute heating during starting of the motors until the load has been accelerated to a predetermined speed.

13. In a motor-control system, in combination, a plurality of driving motors. said motors being provided with commutator cylinders and brushes disposed to engage the commutator cylinders, means for increasing the torque delivered by one motor while the torque delivered by another motor is being decreased at corresponding amount, and a drive for connecting the respective motors to a common load, said drive being adapted to deliver a varying reactive force when receiving a varying torque, whereby a constant etfort to move the load is maintained and the commutator cylinders are oscillated relative to the brushes to distribute heating during starting ot the motors until the load has been accelerated to a predetermined speed.

14. In a motor-control system, in combination, a driving motor provided with an armature, con'unutator cylinder, and commutator brushes, :1 source of power for the motor, means or applying a varying voltage to the motor to develo a varying torque, and means cooperative with the motor to effect an oscillatory movement of the armature to move the commutator cylinder relative to the commutator brushes.

15. In a motor-control system, in combination, a driving motor provided with armature. commutator cylinder and commutator brushes, a source of power for supplying the motor, means for periodically varying, through a predetermined cycle, the voltage applied to the motor, and a resilient drive cooperative with the motor to effect an oscillatory movement of the armature to GfiBCt continuous movement of a commutator cylinder relative to the commutator brushes.

16. A motor-control system, in combina tion, a plurality of driving motors provided. with armatures, commutator cylinders and commutator brushes, a source at power for supplying the motors, means for applying a continuously varying voltage to each of the motors to develop a varying torque, said voltage-carrying means being disposed to cause the application of a constant average voltage to the motors, and means cooperative with motors to effect an osclilatory movement of the arn'iatures in response to the application of the continuously varying voltage to effect an oscillatory movement of the commutator cylinder relative to the com mutator brushes.

In. testimony whereof, I have hereunto subscribed my name this 25th day of June, 1928.

CHARLES C. \VHITTAKER. 

